Microstructure and mechanical properties of consolidated gamma titanium aluminides

Abstract

Microsized γ-TiAl powders with composition of Ti–50Al (at.-%) and Ti–48Al–2Cr–2Nb (at.-%) were consolidated using a rapid consolidation technique called plasma pressure compaction (P²C^®) to obtain samples with near gamma, duplex and fully lamellar microstructure. The consolidated samples exhibited minimal grain growth during consolidation, thereby retaining superior mechanical properties. The mechanical properties varied significantly with microstructure type, grain size and alloy composition. Samples with a duplex microstructure and average grain size of 5 μm exhibited the best set of mechanical properties with flexure strength, ductility, elastic modulus and fracture toughness as high as 1238 MPa, 2·3%, 154·58 GPa and 17·95 MPa m^1/2 respectively. Exposure in air at temperatures >800°C, had an adverse effect on the flexure strength of the consolidated samples.

Keywords:

• AEROSPACE MATERIALS
• RAPID CONSOLIDATION
• INTERMETALLICS
• TITANIUM ALUMINIDE
• HIGH TEMPERATURE
• GRAIN GROWTH
• BENDING
• HARDNESS
• MICROSTRUCTURE
• PROPERTIES